The objective of this project is to characterize dose-response relationships and toxicity of twenty compounds administered by inhalation, (toluene, isobutyl nitrate) dosed feed (amsonic acid), and oral gavage (isoproterenol, dimethyloldihyroxyethyleneura, coumarin, 3,4-dihydrocourmarin, 6-Methylcoumarin, azodicarbonamide, carvone, resorcinal, diethylphthalate, mercuric chloride, padladium chloride, monochloroacetic acid, chloramphenical, cadinenes, C.I. Direct Blue 218 propantheline bromide, and triamterine) to male and female rats and mice in acute, 14-day, 90-day subchronic and 2-year chronic studies. Animals will be treated for 1 day, 14 days, or 13 and 104 weeks. At the end of each study, all animals will be given gross and microscopic histopathologic evaluations. The results of each prechronic study will be used by NTP to establish doses to be used in the next study. The results of the 2-year chronic study will be used by NTP to determine toxicologic and carcinogenic effects of administration of each compound.